New Mexico Geological Society Annual Spring Meeting — Abstracts

Historically, dominant grassland communities have been displaced by woody shrubs over the last 150 years in the Jornada Basin, southern New Mexico. As shrubs invade semi-arid perennial grasslands, the length, number and arrangement of connected bare patches increase which creates transport corridors. Increased growth and coalesces of these connected pathways overtime can result in a nonlinear increase in soil loss and redistribution by wind and water erosion. Implementing remediation strategies that disrupt the growth of these connected transport pathways is a potential soil conservation strategy that can lessen the harmful effects of desertification. Smallscale manipulations were conducted in two high sediment transport environments positioned on a wind erosion dominated landform (e.g. Basin floor) and a water erosion dominated landform (e.g. Bajada). Sediment retention structures were deployed on each landform unit in highly eroded unvegetated gaps. Fallout radionuclide tracers ( ²¹⁰Pb_ex, ₁₃₇Cs, and ⁷Be) were used to derive sediment budgets and to quantify the effect of the structures on soil redistribution rates by wind and water transport. Preliminary results, based on sediment budgets reconstructed from fallout radionuclide inventories, indicate that sediment retention structures are more efficient in modifying soil redistribution in wind dominated systems when compare to water dominated systems.